Paper money identifier

ABSTRACT

An improved currency identifier permits recognition of various denominations of paper currency by blind persons. The identifier includes a housing having a tray along which money to be identified is passed. In one embodiment, a source of light is stationed above the tray and positioned directly under the light source is a series of very small holes formed in the bottom of the tray. The holes are aligned across the tray so that light from the source shines through the center of paper currency passed along the tray, through the holes, and onto a photoelectric cell located beneath the tray. The photocell is connected to a relaxation oscillator circuit and controls the oscillator frequency in accordance with the amount of light passing through the money. The output from the oscillator is connected to a loudspeaker which produces a tone that varies in accordance with the output from the photocell. Since the various currency denomination have distinct printed patterns and thus have different light responsive characteristics, the audible sounds produced can be identified as being representative of a specific bill. In a second embodiment, the photocell and light source are positioned on the same side of the bill to be identified. The light is transmitted onto the bill and a portion of the light is reflected onto the photocell. The reflected light is also distinctive of a particular bill and produces an identifiable tone pattern; however, this embodiment produces a simplified sound pattern since the characteristics identified by the light pattern are only taken from one side of the bill.

United States Patent 1 1 Marchak PAPER MONEY IDENTIFIER [76] Inventor:Frank J. Marchak, 5802 Shoal Creek Blvd., Austin, Tex. 78757 22 Filed:Sept.ll, 1974 21 Appl1No.: 504,931

[52] US. Cl. 340/149 R; 340/149 A Primary ExaminerHarold I. PittsAttorney, Agent, or Firm-Jones, Tullar & Cooper 5 7] ABSTRACT Animproved currency identifier permits recognition of variousdenominations of paper currency by blind persons. The identifierincludes a housing having a tray along which money to be identified ispassed. In one embodiment, a source of light is stationed above the trayand positioned directly under the light source 51 Sept. 16, 1975 is aseries of very small holes formed in the bottom of the tray. The holesare aligned across the tray so that light from the source shines throughthe center of paper currency passed along the tray, through the holes,and onto a photoelectric cell located beneath the tray. The photocell isconnected to a relaxation oscillator circuit and controls the oscillatorfrequency in accordance with the amount of light passing through themoney. The output from the oscillator is connected to a loudspeakerwhich produces a tone that varies in accordance with the output from thephotocell. Since the various currency denomination have distinct printedpatterns and thus have different light responsive characteristics, theaudible sounds produced can be identified as being representative of aspecific bill.

In a second embodiment, the photocell and light source are positioned onthe same side of the bill to be identified. The light is transmittedonto the bill and a portion of the light is reflected onto thephotocell. The reflected light is also distinctive of a particular billand produces an identifiable tone pattern; however, this embodimentproduces a simplified sound pattern since the characteristics identifiedby the light pattern are only taken from one side of the bill.

16 Claims, 4 Drawing Figures PATENTEUSEP 1 6l975 C31 986 A 19 FIG.4

PAPER MONEY IDENTIFIER BACKGROUND OF THE INVENTION The present inventionrelates, in general, to currency identification and, more particularily,to a method and apparatus for currency identification for the blindwhich converts light pattern characteristics of currency intodistinctive audible tones, identifiable by the blind.

A number of devices have been constructed to aid in the identificationof currency, and some of these devices utilize light and photocellcombinations for this purpose. In addition, numerous devices have beenconstructed to aid the blind in reading printed material by utilizing aphotocell to scan the printed material and produce an audible signal inresponse to the output from the photocell. However, most of these priorart devices require a I specific orientation of the bill or printedmatter within the device before an intelligible reading can be obtained,and this in itself produces serious problems for the blind.

Another difficulty with prior devices in that they have, in attemptingto reach a high degree of accuracy, tended to become very complex, andthus have become expensive to purchase and difficult to maintain inworking condition, and accordingly have not been satisfactory. Many ofthese devices have utilized various mechanical indicators which easilybecome misadjusted and which can thereby produce incorrect readings ofcurrency denominations, while others use banks of photocells which notonly are expensive, but which require complex circuitry to provide thedesired indication.

Considerable effort and expense has been expended in the prior art toprovide a highly reliable, maintenancefree, long-lasting, accurate, andeasy to use device for producing an indication of the denomination ofpaper money. Such a device should provide maximum convenience for theuser, be simple in operation, and should provide a reliable, easilyidentified, unique indication of the denomination of the currency beingtested.

SUMMARY OF THE INVENTION It is, therefore, as object of the presentinvention to provide an apparatus which enables the blind to identifypaper currency by converting the dark and light characteristic patternsof the currency into distinctive, identifiable audible signals.

It is another object of the invention to provide an im provedcurrency'identifying apparatus incorporating a circuit for convertinglight signals impinging on a photocell into audible signals representingthe impinging light pattern.

Another object of the invention is to provide a money-identifyingapparatus having a tray which receives the money, and which providesaccurate identification of the currency whether it is placed within thereceiving tray face up or face down.

Briefly. the present invention accomplishes the foregoing and otherobjectives by the provision of a currency identifier which incorporatesmeans for distinguishing variations in the light reflectance of theprinted patterns on paper currency. The identifier includes means forcreating a predetermined light path between a source and a photocell.The currency to be identified is passed through this path, causingvarying amounts of light to reach the photocell, in accordance with theconfigurations printed on the bill. This variation in light changes theoutput of the photocell, which causes the frequency of an oscillatorcircuit to change. The oscillator drives a loudspeaker, and the lightvaria tions thus cause corresponding changes in the sounds emitted asthe bill is moved through the identifier. Each denomination of papercurrency produces a characteristic sound pattern from the apparatus ofthe present invention, the sound variations corresponding to the changesin the shades of color and the presence or absence of printing on theportion of the bill passing through the light path as the bill is movedthrough the identifier, with light colors emitting a higher pitchedsound than the darker colors.

In a first embodiment of the invention, the light path is constructed sothat light passes through the bill to the photocell. With thisarrangement, the device is sensitive to variations in the transmissionof light through the bill, and these variations are the same whether thebill is face up or face down. The money identifier consists of a housingshaped to provide an elongated channel, or tray, which is adapted toreceive paper currency to be identified and which defines a path alongwhich the currency is drawn for identification. Mounted on the housingand extending over a portion of the tray is a light box which carries aconvenient source of light and which includes a suitable opening fordirecting light onto a selected portion of the tray. Immediately belowthe light box and arranged at approximately the center of the pathfollowed by the currency is a series of small holes in the tray. Aphotocell is located within the housing below the holes in the tray toreceive light from the source. Preferrably, the holes are located in astraight line transverse to the path followed by the currency, andextend about one-half inch across the center thereof, where variationsin the printed pattern are at a maximum.

As a money bill is pulled along the housing tray, it travels through thelight path defined between the light source and the photocell, causingvariations in the amount of light passing through the bill and strikingthe photocell. These variations are unique for each denomination ofcurrency, and correspond to the pattern printed on both sides of thebill.

Also mounted within the housing is an oscillator circuit having afrequency of operation which is responsive to the magnitude of thephotocell resistance. The output from the oscillator is an audiofrequency which is fed to a loudspeaker mounted in the housing. Thespeaker thus produces a sound which varies in frequency in accordancewith the pattern of the bill passing through the light path of theidentifier device. Since each denomination of currency has a uniqueprinted pattern, each will produce a unique pattern of sound which canbe identified by the user of the device to accurately identify eachdenomination bill.

In a modified form of the invention, the locations of the light sourceand photocell can be reversed, with the photocell being located abovethe path of the bill to be identified. However. this arrangement is lessdesirable than the previously described relationship, for it makes itmore difficult to replace light bulbs when they burn out. I

In another modification of the invention, both the light source and thephotocell can be placed on the same side of the path followed by thebill to be identified, in which case the device responds to the lightreflected from the bill, rather than that which passes through it. Thelight reflected to the photocell varies in accordance with the patternon the side of the bill facing the photocell system, and produces acorresponding output sound. The photocell system may be either above orbelow the path followed by the currency. Although this arrangementrequires that the operator be able .to distinguish between the obverseand reverse faces of each denomination of bill, and thus may requirethat the operator place the bill with the proper face up, it has theadvantage of producing a less complex sound pattern which is more easilyrecognized by I an operator. However, the first-described embodiment iseasier to operate, since it does not matter which face of the bill isup, and accordingly provides a faster identification of denomination.

BRIEF DESCRIPTION OF DRAWINGS The foregoing and additional objects,features and advantages of the invention will be apparent to thoseskilled in the art from the following description, taken inconjunctionwith the accompanying drawings, in

.which: 7

FIG. 1 is a perspective view of the exterior housing of a currencyidentifier constructed in accordance with the present invention;

FIG. 2 is a cross-sectional view of the currency identifier of FIG. 1taken along line 22, and illustrating a first embodiment of thephotocell system;

FIG. 3 is a cross-sectional view of a light box used in anotherembodiment of the currency identifier constructed in accordance with thepresent invention; and

FIG. 4 is a schematic diagram of a preferred form of the electroniccircuitry which can be used in the photocell systems of the embodimentsof FIGS. 2 and 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIG. 1there is illustrated in perspective view a currency identifier 10, theFigure showing the general appearance of the exterior housing of thecurrency identifier of the present invention. The identifier consists ofgenerally horizontal and up standing portions, 12 and 14 respectively,forming an L-shaped housing. The housing itself may be formed of anyrigid material suitable for the purpose, such as metal or plastic. Fixedto the top surface 15 of the horizontal portion 12 of the housing, as bybolting or otherwise, is a tray 18, which generally is formed of thesame material as the housing, and along which money to be identified ispassed. The tray 18 positions currency relative to a light box 20, whichis fixed to the front wall of the upstanding portion 14 of the housingby any suitable means, the light box being cantilevered from portion 14and extending transversely across, but spaced above, the tray.

As shown in FIGv 2, a plurality of small apertures 22 are formed throughthe center portion of the tray 18 and extend transversely thereacross,the apertures being aligned with the light box and being positionedacross the center portion of the tray. The apertures 22 extend acrossapproximately one-half inch of the tray, so that when tray 18 is used asa guide for the currency, the apertures will underlie the centrallongitudinal portion of each bill inserted into the tray and drawn underthe light box 20. It will be understood that the apertures could bereplaced by a corresponding narrow slot.

Rails 24 and 26 are provided. at the left and right ends of the tray, asviewed in FIG. 1, and serve to inform the operator of the identifier 10of the location of the bill with respect to the light box' 20,longitudinally along the tray. Similarly, the corner 28, formed by theintersection of the front surface of the upstanding portion 14 and theback edge of the tray, cooperates with a front rail 29 formed along thefront edge of the tray to center the bill transversely on the tray andalign its center with the apertures 22.

The light box 20 is offset to the left side of the housing, as viewed inFIG. 1, so that a currency bill can be placed flat in the tray to theright of the light box before it is drawn under box 20. This enables ablind operator to correctly position a bill in the tray for determiningits denomination with little effort, and to insure consistently correctoperation. To the left of the light box the tray need only be largeenough to accommodate about one-half the length of a bill, since it isnot generally necessary to pass a bill completely through the device toobtain an accurate identification; usually the identifying soundcharacteristics can be recognized from just a portion of the bill. Theprovision of the end rail 24 with respect to the photocell system withinthe light box permits the operator to position bills accurately underthe light box to detect specific characteristics of variousdenominations.

To assist the operator in feeding the bill through the photocell lightpath, the bottom of the light box near the surface of tray 18 is taperedby means of two sloped wall portions 30 and 31 (FIG. 1), forming entryslots at the bottom edges of the light box to make it easier for a billto slide into the opening 32 between the light box and the surface 'oftray 18, where the denomination of the bill is to be read.

Mounted at a convenient location, such as on the top of the upstandinghousing portion 14, is a push-button switch 33 for switching the powerto the identifier 10 on and off and a potentiometer control knob 34 forvarying the tone-volume control. The potentiometer may be rotated toincrease or decrease the pitch and volume of the audible signal producedby the present device to adjust it to the personal preference of theoperator. The functions of switch 33 and tone-volume control 34 will bediscussed again hereinbelow.

The interior of the lightbox 20 is shown in FIG. 2 as incorporating alight source 40, such as a standard prefocussed flashlight bulb, mountedin a socket 42 which is attached by a suitable bracket 44 to the uppersurface of the light box 20. The lamp 40 directs its beam downwardlythrough an aperture 46 formed in the bottom of the light box, wherebylight from the bulb is directed onto the apertures 22. The upper surface15 of the horizontal housing portion 12 has a rectangular opening 48which is directly below and in alignment with the apertures 22 in tray18. A photocell 50 is mounted to the under side of surface 15, andcovers the opening 48 so that any light passing therethrough illuminatesthe photocell. If desired, and in a preferred form of the invention,some means for directing the light from source 40 through the aperture46 and onto the photocell 50 can be used, such as a cylindrical shroud52 which confines the light to a downward direction. Source 40 is'electrically connected by way of lines 53 and 54 to the remainingcircuit elements, to be described, housed in an electronics package 56.Photocell 50 is also connected to this circuitry package through lines58 and 60. The arrangement of the light source is such that lightfromsource 40 shines through aperture 46 onto the currency positioned ontray 18. Light passes through the bill and falls on photocell 50 inaccordance with the printed pattern on the two sides of the bill..Thevarying light striking the photocell causes a varying electricalresistance on lines 58 and 60 to the processing circuitry 56.

An alternate form of the apparatus of the present invention is shown inFIG. 3, which is a partial, front view of the housing 10, with only thelight box 20' and the tray 18 shown in section to illustratetherelationship of the photocell system to the path followed by the bill tobe identified. Elements in common with FIG. 2 are given the numeralsused in FIG. 2, while equivalent, but different, elements are primed.Thus, the light source 40 in this embodiment is mounted in a modifiedform of the light box 20' by means of socket 42 and bracket 44, and iselectrically connected to the electronic circuitry within housing by wayof lines 53 and 54 which pass into the housing through an opening 56 inthe front wall of housing portion 14. Similarly, photocell 50 isconnected to the circuitry (to be described) through lines 58 and 60. Inthis embodiment, the light box takes a different form to accommodateboth the light source and the photocell, and incorporates a supportframe 61 connected to the upstanding portion 14 of housing 10 bybrackets 62. The frame 61 carries the light box cover portion 20 whichis removable to permit access to the photocell system mounted on theframe. Tray 18 is fixed to the upper surface of the horizontal housingportion 12, but does not require the small apertures needed, in theembodiment of FIG. 2, although the end and rails 24, 26 and 29 are stillprovided to guide the placement of the currency bill in the tray forexposure to the light source.

The light box 20, is formed with a complex bottom surface shape to notonly facilitate insertion of a bill between the box 20 and the tray 18',but to direct the light from source 40 onto the bill for reflection tothe photocell. Thus, the bottom surface, as defined by frame 61,incorporates downwardly tapered portions 63 and 64 which facilitateinsertion of paper currency from the tray 18 into space 32, and upwardlyangled central portions 65 and 66 which accommodate a slot 67 and thephotocell 50, respectively. Theportions 63, 64, 6 5 and 66 form agenerally W-shaped bottom for the light box, with the lowest portions ofthe bottom being closely spaced from the tray 18' to provide the narrowspaces 32 adapted to receive the currency to be identified.

Light source 40 is mounted by bracket 44 to the interior of wall 63, themounting serving to direct light from the bulb through an aperture 67formed in the wall 65. The aperture 67 extends transversely across thelongitudinal center axis of the tray, and is so positioned and sizedthat light from the bulb will be reflected from the center portion ofthe surface of any currency positioned on tray 18 and drawn throughslots 32 upwardly into the photocell 50. It will be understood that. theamount of light reflected, and thus the output from the photocell onlines 58, 60, will depend upon the surface characteristics of thecurrency; i.e., upon the printed pattern thereof. Changes in reflectedlight from the bill cause the resistance of the photocell to change,creating a varying output on lines 58 and 60 to the electroniccircuitry.

The electronic circuitry used in the embodiments of both FIGS. 2 and 3is illustrated in FIG. 4, to which reference is now made. As indicated,the present money identifier operates from a conventional source of l15v. alternating current, as by way of a plug 70. The A.C. input isapplied by way of lines 72 and 74 through the contacts 76 and 77 ofpushbutton switch 32 to the primary winding 78 of an input transformer80. When depressed, pushbutton switch 32, which may be of thepush-to-close, push-to-open type, closes the circuit through thetransformer 80 and turns the system on. Light source 40 is connected inparallel across a secondary winding 82 of transformer 80. A resistor 84in series with the bulb limits the current passing through light source40 and thus serves to regulate its brightness. A full wave rectifierconsisting of diodes 88, 90, 92 and 94 is connected across secondarywinding 82 via lines 96 and 98 to provide a source of direct current forthe remainder of the circuit on lines 100 and 102. A capacitor 104 isconnected across the output lines 100, 102 to provide a constant outputvoltage of approximately 9 volts d.c. If desired, a 9 volt battery couldbe placed across lines 100, 102 as a substitute for the ac. rectifiernetwork.

Connected across lines 100 and 102 is an R.C. series network consistingof a capacitor 106 which is charged through a resistor 108, photocell 50and the adjustable resistance of a potentiometer 110 having a resistance112 and a movable tap 114 adjustable by means of knob 34. Variation ofresistor 112 provides the tonevolume control described above withrespect to FIG. 1. A resistor 115 may be provided across potentiometer 110 to limit the resistance of the network. The capacity of capacitor 106and the value of the total resistance in series with it determines thetime required for it to charge to a preselected voltage level.

The RC. network is connected to a unijunction transistor 116 to controlits conduction, and to form a frequency controlled relaxationoscillator. The junction between potentiometer 110 and capacitor 106 isconnected by way of line 118 to the emitter 120 of transistor 116, whileline 102 is connected through a bias resistor 122 to the base 2 of thetransistor, indicated at 124. The base 1 connection 126 of thetransistor is connected through the drive coil 128 of a loudspeaker 130to line 100.

When the charge across capacitor 106 builds to the emitter-to-basebreakdown voltage of transistor 116, the transistor becomes forwardbiased and conducts. Capacitor 106 then discharges through line 118,transistor 116 and speaker coil 128, causing a sonic pulse. Uponcompletion of the discharge, the transistor becomes reverse biased andnonconductive until the voltage on capacitor 106 again builds to thebreakdown value. With a given value of capacitor 106, the frequency withwhich the capacitor 106 charges and discharges depends on the combinedresistance values of resistor 108, potentiometer 110, shunt resistor115, and the resistance exhibited by the light sensitive photocell 50.

Once the value of potentiometer 110 is set by adjusting arm 114, thefrequency of the relaxation oscillator will depend solely on the valueof the resistance of photocell 50, which resistance varies with theamount of light striking the surface of the photocell device, and inparticular with the amount of light from light source 40 which istransmitted through or is reflected from a currency bill. The limitingresistors 108 and 115 establish the minimum and maximum resistances,respectively of the RC. network and thus limit the maximum and minimumrates at which the capacitor 106 will charge to the breakdown voltage oftransistor 1 16. In this manner the maximum frequency of the oscillator,and thus the maximum tone pitch produced by the loudspeaker, isestablished at a level below the supersonic sounds which might hurt theears of seeing eye dogs which often accompany blind persons. The maximumresistance of the RC. circuit establishes the lowest tone frequenciesproduced by the circuit." It will be understood that resistor 108 and115 may be made adjustable, if desired; to permit compensation forvariations in other components in the circuit, and that a variable gainamplifier r nay'be provided between the oscillator and the loudspeakerwith a volume control knob mounted on the housing for convenient controlof the sound produced by the speaker.

In operating the money identifier of this invention, a currency bill tobe identified is placed flat in tray 18 or 18' and is located to theright of the light box, as viewed in FIG. 1, with the backedge of thebill against the upright portion 14 of the cabinet and the left end ofthe bill against'the light box. The tray, housing, and light box are soarranged as to facilitate convenient and consistent correct placement ofthe bill in the identifier by a blind operator. Using his fingers, theoperator then feeds the bill into the space below the light box, andthus into the path of the light beam from source 40. The bill is thendrawn steadily through the identifier so that variations in the opticalproperties of the printing on the bill will cause variations in thelight path between source 40 and photocell 50. In the first embodimentdescribed above, the light path is through the bill,

and the variations in the pattern printed on both sides of the billcause corresponding variations in the resistance of the photocell, andthus in the frequency of the sound produced by the relaxationoscillator. In the second embodiment described above, the light path isreflected from the surface of the bill, so that variations in theprinted pattern on only one side of the bill cause correspondingvariations in the sound produced by the identifier. Both embodimentsproduce unique and identifiable sounds, although the sound produced bythe first embodiment is more complex and thus more difficult to learn,since it is a composite of the patterns of both sides of the bill.Although producing a simpler sound pattern, the second embodiment mayrequire two passes of the bill through the device since the faces of alldenominations of bills have very similar light and dark patterns and maypresent difficulties in identification. In this event, it may benecessary to turn the bill face down and feed it through the light pathagain for identification. With both embodiments there may be slightdifferences in sound, depending on which end of the bill is introducedinto the path first; however the difference is slight and notsignificant for purposes of bill identification since the readings aretaken along the longitudinal center of the bill.

To illustrate the manner in which the present money identifier operates,consider a five dollar bill inserted into the FIG. 2 embodiment, wherelight passes through the bill. The $5.00 bill is very symmetrical exceptthat the word FIVE appears in big light print on the face to the rightof the picture of Lincoln. The back side is perfectly symmetrical exceptthat the illumination of the'Lincoln Memorial is from the left side andproduces a light spot between the second and third columns of thepicture of the Lincoln Memorial. The columns are light and the shadowsbehind them are dark. 'When the picture of these columns passes thru thelight beam, alternate high and low tones are produced by the oscillator.They are very distinct and of the same pitch and same distance apart,especially in the center of the bill. When the bill is moved back andforth from a point where the left edge of the bill is inch from theleftedge of the tray to the left edge of the tray, it sounds like someonepulling a stick along a picket fence.

When moving a $20.00 bill thru the instrument, all of the tones are deepwith very few high pitched tones. The most distinguishing features ofthe $20.00 bill are the overall deep tones, the short high tone an inchin from either end, and the alternate high and low tones in the centerof the bill near the end of the movement. The face of the $20.00 bill issymmetrical except for the word TWENTY to the right of Jackson spicture. These letters are very faint and do not show up clearly as thebill passes through the instrument. The back side is symmetrical exceptfor trees covering the left side of the picture of the White House, butnot the right hand side. The trees are very dark and produce the lowtones, lower than any other bill. About an inch from either end, a lightarea (high pitch) exists for about A inch. This occurs when the left endof the bill is about 2% inches from the left end of the tray. This makesidentification between a $5.00 and $20.00 simple because the light areaon the five is about 4 inch long.

Another distinguishing feature of the $20.00 bill is the columns in thepicture of the White House. There are six columns and five dark areasbetween them. The columns are located in the center of the bill. Analternate high and low pitch tone can be heard when the left edge of thebill is moved from a point /2 inch away from the left edge of the trayto the edge of the tray.

The $10.00 bill creates sound patterns very similar to the $5.00 billbut does not have the alternate high and low patterns caused by thecolumns on the $20.00 bill and does not have the alternate high and lowpatterns in the center which are characteristic of the $20.00 bill. Themajor identifying point is a dark area (low tone) created by shadowsabout Vs inch long between two columns of the picture of the TreasuryBuilding'fWhen the bill is fed into the identifier with the back up andright side up, this low tone occurs when the left edge of the bill isabout 1 inch from the left edge of the tray. It also occurs when thebill is inserted face up, but with Hamiltons picture upside down. If thebill is inserted in the other two directions, it will not appear unlessthe left edge of the bill is lifted so it can pass over the left edge ofthe tray about A inch.

The sounds emitted when a $1.00 bill is passed through the instrument donot have a pattern that is as easily identified as the other bills. Thesounds are a series of high and low tones, none of very long duration.

One distinctive feature is a light spot (high pitch) that occurs whenthe left end of the bill is about 1% inches from the left edge of thetray. This light area is only about A; inch long and exists on eitherside of the word ONE. The areas on either end of the bill, are mostlydark (low' pitched) before this area. This high pitch is produced wheneither end of the bill is'fed into the instrument. Another distinctivefeature is a very low tone at a position where the left edge of the billis about $41 inch from the left edge of the tray. This is caused by acombination of a dark area of George Washingtons picture on the faceside and areas of the letter ONE on the back side and is heardregardless of which end of the bill is inserted.

In similar manner, distinctive sounds are produced by variousdenomination bills inserted into the device of the second embodiment,shown in FIG. 3. Thus it can be seen that with a proper amount oftraining, the present invention can be used as a valuable aid for blindpersons in accurately and quickly identifying paper currency of variousdenominations. The invention is designed to operate effectively with aminimum of training and manual effort, and with minimum require mentsfor handling the bills before a reading can be obtained. Although theinvention is disclosed in terms of specified embodiments, it will berecognized that numerous variations and modifications of the inventioncan be constructed without departing from the true spirit and scopethereof as defined in the following claims.

I claim:

1. A currency identification apparatus for aiding blind persons inidentifying currency, comprising:

means generating a light beam;

photoresponsive means for receiving said light beam,

the resistance of said photoresponsive means varying in accordance withthe amount of light received;

means for directing said light beam along a path between said generatingmeans and said photoresponsive means which path includes the currency tobe identified,

capacitor means connected in electrical series with said photoresponsivemeans, said capacitor means being charged through said photoresponsivemeans, so that the time required to charge said capacitor is directlyproportional to the resistance value of said photoresponsive means;

transistor means connected to said capacitor means,

said transistor being biased into conduction whenever the charge on saidcapacitor reaches a predetermined level; and

loudspeaker means connected to said transistor means, said capacitormeans discharging through said speaker means to produce an audible tonewhenever said transistor conducts.

2. The currency identification apparatus of claim 1, further including ahousing for positioning said light means relative to saidphotoresponsive means.

3. The currency identification apparatus of claim 2, wherein saidhousing includes a tray for positioning said currency relative to saidhousing and in said path of said light beam, and wherein said lightmeans and said photoresponsive means are on opposite sides of said tray,said tray having at least one small aperture extending approximatelyone-half inch across the center portion of said tray so that lightpasses through the center portion of currency located on said tray andimpinges on said photocell.

4. The currency identification apparatus of claim 1, further including afirst resistor means in series with said photoresponsive means andcapacitor means for limiting the minimum resistance in series with saidcapacitor means, thereby limiting the highest pitched audible toneproduced by said loudspeaker.

5. The currency identification apparatus of claim 1 further including asecond resistor means in series with said photoresponsive means and saidcapacitor means, for limiting the maximum resistance in series with saidcapacitor means, thereby limiting the lowest pitched audible toneproduced by said loudspeaker.

6. The currency identification apparatus of claim 1, further including athird adjustable resistor means in series with said photoresponsivemeans and said capacitor means for setting the audible tones produced bysaid loudspeaker to a desired frequency range.

7. The currency identification apparatus of claim 4 further including asecond resistor means in series with said photoresponsive means and saidcapacitor means for limiting the maximum resistance in series with saidcapacitor means, thereby limiting the lowest pitched audible toneproduced.

8. The currency identification system of claim 7 wherein said apparatusfurther includes a third adjustable resistor means in series with saidphotoresponsive means and said capacitor means for selecting a desiredfrequency range for the audible tones produced.

9. The currency identification apparatus of claim 2, wherein saidhousing includes tray means for positioning said currency in said pathof said light beam, and wherein said light means and saidphotoresponsive means are on the same side of said tray so that saidlight beam is reflected from the surface of said currency into saidphotoresponsive means.

10. The currency identification apparatus of claim 9, further includinga first resistor means in series with said photoresponsive means andcapacitor means for limiting the minimum resistance in series with saidcapacitor means and thereby limiting the highest pitched audible toneproduced.

11. The currency identification system of claim 10 wherein saidapparatus further includes a second resistor means in series with saidphotoresponsive means and said capacitor means for limiting the maximumresistance in series with said capacitor means and thereby limiting thelowest pitched audible tone produced.

12. The currency identification apparatus of claim 11, further includinga third adjustable resistor means in series with said photoresponsivemeans and said capacitor means for setting the audible tones produced toa desired frequency range.

13. The currency identification apparatus of claim 1, wherein said meansfor directing said light beam includes light box means supporting saidlight beam gencrating means, and aperture means in said box means fordirecting said light beam onto said currency.

14. The currency identification apparatus of claim 13, wherein saidlight box means further includes means for supporting saidphotoresponsive means adjacent said light beam generating means, and inthe path of light reflected from the surface of said currency.

15. The currency identification apparatus of claim 13, including meansfor mounting said photoresponsive means adjacent said light beamgenerating means and in the path of light transmitted through saidcurrency. 16. The currency identification apparatus of claim 13, furtherincluding tray means for receiving said currency, said tray meanslocating said currency for movement through said path, whereby uponmotion of the currency the amount of light from said light generatingmeans striking said photoresponsive means will vary in accordance withvariations in the printed pattern on said currency to produce a varyingoutput tone characteristic of said currency.

1. A currency identification apparatus for aiding blind persons inidentifying currency, comprising: means generating a light beam;photoresponsive means for receiving said light beam, the resistance ofsaid photoresponsive means varying in accordance with the amount oflight received; means for directing said light beam along a path betweensaid generating means and said photoresponsive means which path includesthe currency to be identified, capacitor means connected in electricalseries with said photoresponsive means, said capacitor means beingcharged through said phoToresponsive means, so that the time required tocharge said capacitor is directly proportional to the resistance valueof said photoresponsive means; transistor means connected to saidcapacitor means, said transistor being biased into conduction wheneverthe charge on said capacitor reaches a predetermined level; andloudspeaker means connected to said transistor means, said capacitormeans discharging through said speaker means to produce an audible tonewhenever said transistor conducts.
 2. The currency identificationapparatus of claim 1, further including a housing for positioning saidlight means relative to said photoresponsive means.
 3. The currencyidentification apparatus of claim 2, wherein said housing includes atray for positioning said currency relative to said housing and in saidpath of said light beam, and wherein said light means and saidphotoresponsive means are on opposite sides of said tray, said trayhaving at least one small aperture extending approximately one-half inchacross the center portion of said tray so that light passes through thecenter portion of currency located on said tray and impinges on saidphotocell.
 4. The currency identification apparatus of claim 1, furtherincluding a first resistor means in series with said photoresponsivemeans and capacitor means for limiting the minimum resistance in serieswith said capacitor means, thereby limiting the highest pitched audibletone produced by said loudspeaker.
 5. The currency identificationapparatus of claim 1 further including a second resistor means in serieswith said photoresponsive means and said capacitor means, for limitingthe maximum resistance in series with said capacitor means, therebylimiting the lowest pitched audible tone produced by said loudspeaker.6. The currency identification apparatus of claim 1, further including athird adjustable resistor means in series with said photoresponsivemeans and said capacitor means for setting the audible tones produced bysaid loudspeaker to a desired frequency range.
 7. The currencyidentification apparatus of claim 4 further including a second resistormeans in series with said photoresponsive means and said capacitor meansfor limiting the maximum resistance in series with said capacitor means,thereby limiting the lowest pitched audible tone produced.
 8. Thecurrency identification system of claim 7 wherein said apparatus furtherincludes a third adjustable resistor means in series with saidphotoresponsive means and said capacitor means for selecting a desiredfrequency range for the audible tones produced.
 9. The currencyidentification apparatus of claim 2, wherein said housing includes traymeans for positioning said currency in said path of said light beam, andwherein said light means and said photoresponsive means are on the sameside of said tray so that said light beam is reflected from the surfaceof said currency into said photoresponsive means.
 10. The currencyidentification apparatus of claim 9, further including a first resistormeans in series with said photoresponsive means and capacitor means forlimiting the minimum resistance in series with said capacitor means andthereby limiting the highest pitched audible tone produced.
 11. Thecurrency identification system of claim 10 wherein said apparatusfurther includes a second resistor means in series with saidphotoresponsive means and said capacitor means for limiting the maximumresistance in series with said capacitor means and thereby limiting thelowest pitched audible tone produced.
 12. The currency identificationapparatus of claim 11, further including a third adjustable resistormeans in series with said photoresponsive means and said capacitor meansfor setting the audible tones produced to a desired frequency range. 13.The currency identification apparatus of claim 1, wherein said means fordirecting said light beam includes light box means supporting said lightbeam generating means, and aperture means in said box means fordirecting said light beam onto said currency.
 14. The currencyidentification apparatus of claim 13, wherein said light box meansfurther includes means for supporting said photoresponsive meansadjacent said light beam generating means, and in the path of lightreflected from the surface of said currency.
 15. The currencyidentification apparatus of claim 13, including means for mounting saidphotoresponsive means adjacent said light beam generating means and inthe path of light transmitted through said currency.
 16. The currencyidentification apparatus of claim 13, further including tray means forreceiving said currency, said tray means locating said currency formovement through said path, whereby upon motion of the currency theamount of light from said light generating means striking saidphotoresponsive means will vary in accordance with variations in theprinted pattern on said currency to produce a varying output tonecharacteristic of said currency.